/*
 * Copyright (C) 2025 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package app.cash.redwood.ui.core.api

import kotlinx.serialization.Serializable

/**
 * Use this to request focus for a target widget.
 *
 * To use this, first create an instance in your composition:
 *
 * ```
 *   val nameFieldFocusRequester = rememberFocusRequester()
 * ```
 *
 * Next, attach the focus requester to a single widget using its modifier:
 *
 * ```
 * TextInput(
 *   modifier = Modifier.focusRequester(nameFieldFocusRequester),
 *   state = nameState,
 *   hint = "full name",
 * )
 * ```
 *
 * Finally, activate the focus requester in response to an appropriate event:
 *
 * ```
 * Button(
 *   text = "Submit",
 *   onClick = {
 *     if (nameState.text.isEmpty()) {
 *       nameFieldFocusRequester.requestFocus()
 *     }
 *     ...
 *   }
 * )
 * ```
 */
@Serializable(with = FocusRequesterSerializer::class)
public interface FocusRequester {
  public fun requestFocus()
}
